In recent years, there was reported an article that an immune obtaining response equivalent to a hypodemic administration and a muscle administration can be obtained by administering influenza vaccine in a situation of making an upper layer region of a skin where a lot of immunocompetent cells exist as a target region even if the applied dose is reduced. Therefore, it is possible to reduce the applied dose by administering the influenza vaccine into an upper layer region of a skin, so that there is a possibility that more people can be inoculated with the influenza vaccine. Note that the wording “upper layer region of the skin” indicates “epidemis” and “dermis” within the skin.
As an administration method of medicine to an upper layer region of a skin, there have been known methods using a single needle, multiple needles, a patch, gas and the like. Then, when taking stability, reliability and manufacturing cost of the administration into account, the method using a single needle is the most suitable as the administration method to the upper layer region of the skin. As a method of administering vaccine to an upper layer region of a skin by using this single needle, there has been known a Mantoux method from old times. The Mantoux method is a method in which medicine of around 100 μL is administered by inserting a needle having a needle tip of short bevel with a size of generally 26 to 27 gauge by an amount of around 2 mm to 5 mm from an oblique direction of around 10° to 15° with respect to the skin.
However, in the Mantoux method, the procedure thereof is difficult, and the procedure is left up to the skill of a doctor who carries out the injection. In particular, there is a possibility that an infant may move at the time of administration, so that it is difficult to administer influenza vaccine by the Mantoux method. Therefore, there is required development of a device which can easily administer vaccine at the upper layer region of the skin.
In Patent Document 1, there is described an injection apparatus in which a limiter having a skin contact surface is connected to a needle hub of an injector. The limiter of the injection apparatus described in this Patent Document 1 is formed in a tubular shape covering the periphery of the needle tube and includes a skin contact surface from which the injection needle protrudes. This limiter restricts the length of the injection needle (protrusion length) protruding from the skin contact surface to the range of 0.5 mm to 3.0 mm and the medicine injected from the injection needle is made to be administered into the inside of the skin.
Also, In Patent Document 2, there is described an apparatus relating to a sticking adjuster for an injection needle and an injection needle assembly provided with that adjuster which prevent the injection needle from being stuck more deeply than an aimed depth. Within the sticking adjusters for injection needles disclosed in this Patent Document 2, there exists a sticking adjuster for an injection needle which closely-contacts with the periphery of the injection needle and which includes a skin contact surface.
Meanwhile, it sometimes happens that an injector is used by sucking-in medicine from a vial. The vial is a medicine storage container in which medicine can be preserved for an extended time in a liquid or freeze-dried state. An opening portion of this vial is normally sealed with a rubber stopper having a thickness of 3 mm to 5 mm. This rubber stopper is designed such that it does not permit leakage of the medicine therethrough even when it is repeatedly pierced by a needle tube. Therefore, most of vaccines, which are used often for group vaccination, are sucked-in from vials.
The limiter described in the Patent Document 1 and the sticking adjuster for the injection needle described in the Patent Document 2 are constituted so as to include an injection needle having a shortened protrusion length (for example, 0.5 mm to 3.0 mm) such that medicine can be administered at the upper layer region of the skin. Therefore, it becomes impossible for the injection needle to pass through the rubber stopper of the vial and it was not possible to use it in the way of sucking-in medicine from the vial.
For example, if it is before attaching the limiter disclosed in the Patent Document 1 to the needle hub of the injector, it is possible to suck-in medicine from the vial by using the injector. Also, if it is before attaching the sticking adjuster for the injection needle disclosed in the Patent Document 2 to the injector, it is possible to suck-in medicine from the vial by using the injector.